Dielectric Material that does not readily conduct Electricity, i.e., an Insulator (see Insulation). A good dielectric resists breakdown under high Voltages, does not draw appreciable Power from the Electric Circuit, and has reasonable physical stability. Dielectrics are used to separate the plates of a Capacitor. The dielectric strength is a measure of the maximum voltage (see Potential) that a dielectric can sustain without significant Conduction .